1. Field of the Invention
The present invention relates to copying machine control systems, and particularly to a copying machine control system for controlling copying machines by transmitting data for controlling the copying machines to a centralized control unit on a control center side.
2. Description of the Related Art
A system for controlling a plurality of copying machines is disclosed in U.S. Pat. No. 4,583,834. In this disclosed system, various information of copying machines such as the total number of copies, troubles, remaining quantities of copy sheets and toner are transmitted to a computer. The computer processes the transmitted information and feeds back instructions to copying machines.
According to such a system, a plurality of copying machines supplied to users are connected to a centralized control unit through a communication network such as telephone lines for remote control of the copying machines. The centralized control unit is provided at a control base, and the controlling party receives with the centralized control unit the information transmitted from respective copying machines. Then, controlling works such as the issue of bills corresponding to the number of copies and dispatch of servicemen corresponding to the troubles are made.
Since general copying machines do not have functions of communicating with a centralized control unit through a communication network, a data terminal is attached to a copying machine for communication when configuring said system. This data terminal collects various information from the copying machine and communicates with the centralized control unit on the basis of the collected information.
In communicating with the data terminal, the centralized control unit has to recognize at which user the data terminal in communication is provided. If it doesn't, a bill will be issued on the basis of the information for a different user. Accordingly, when providing a data terminal at a certain user, the system must be configured so that the centralized control unit can recognize the user at which the data terminal is provided.
That data terminal communicates with the centralized control unit, but an object of the control is the copying machine. Accordingly, when a data terminal is optionally provided for a copying machine, it is necessary that the data terminal is correctly connected to the copying machine which is objective to the control. That is to say, when the centralized control unit recognizes a certain data terminal, if the data terminal is erroneously connected to a different copying machine, the centralized control unit will control the different copying machine. Especially, when a plurality of copying machines are provided at a single user, each data terminals must be correctly connected to each corresponding copying machine.
Now, data terminals communicate with the centralized control unit through a communication network, so that communication may be erroneously made with a different party due to cross or errors in the communication network. Accordingly, the data terminals and the centralized control unit must confirm destinations of communication with each other. Also, if the third party comes in through the communication network, information in the system may be lost or broken, so that it is required to enhance the safety of information communication among data terminals and the centralized control unit.
Also, the communication among data terminals and the centralized control unit is made when predetermined conditions are satisfied. For example, when a trouble occurs in a copying machine, the data terminal calls the centralized control unit. In this case, appropriate communication corresponding to the operational conditions of the copying machine is required, and it is necessary to generate warning at an early time in order not to make the trouble worse.